For marketplace websites like eBay and Etsy, the cutoffs typically depend on the seller. So when purchasing a gift, take a close look at each seller’s profile and product page before checking out to ensure a gift will arrive in time for Christmas. (For sites like Etsy, the seller profile is usually attached to the page for the product being sold.)

For Amazon, which will sell just about anything you need for your holiday shopping,the free shipping cutoff for gifts to arrive by Christmas is tomorrow. Its standard shipping cutoff is Wednesday. After that, it’s still possible to order gifts, but it will require expedited shipping to ensure they arrive on time. The critical cutoff is 3 p.m. eastern time on Saturday for a gift to arrive on time with one-day shipping, unless it’s available for local delivery. In that case, you can order as late as December 24.

Many other major online retailers, like Wal-Mart and Best Buy, have standard shipping cutoffs on Tuesday or Wednesday for the gift to arrive by Christmas. Like Amazon, you can still order it a few days after the cutoff, but you will have to use rush shipping options. Sites like Wal-Mart also offer the option of purchasing and picking the gift up in a nearby store.

For Apple gifts directly from Apple’s website, the cutoff dates vary, but you have until midnight tonight to order an iPhone 5 in order to receive it by December 25. The iPad Mini cutoff date has passed, but most other Apple gifts are still available if ordered by the end of the day.

If you’re shopping for an iPhone alternative, like a smartphone running Google’s Android operating system, AT&T, Sprint and Verizon are all offering holiday shipping, provided the order comes before the end of the week. Get your order in by Wednesday, to be on the safe side.

Ordering after these cutoff dates does not mean that the order will never arrive — it just doesn’t ensure that the gift will arrive in time for Christmas.

Alternatively, instead of ordering a physical gift, you can gift an App or a service – which doesn’t have any kind of shipping delay, because it’s a digital product.